Line switch and connection



Nov. 27,1923. 1,475,499

F. A. LUNDQUIST LI'NE SWITCH AND CONNECTION 2 Sheets-Sheet 1 Original Filed Aug. 5, 1918 Nov. 27, 1923. ,47

F. A. LUNDQU|ST' LINE SWITCH AND CONNECTION Original Filed Aug.'5, 1918 2 Sheets-Sheet Z Patented Nov. 27, 1923.

UNITED STATES PATENT'OFFSICE- FRANK A. LUNDQUIST, or CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASS GNMENTS,

TO HENRY S. CONRAD, TRUSTEE.

LINE SWITCH AND CONNECTION.

Application filed August 3, 1918, Serial No. 248,104. Renewed June 4, 1923.

To all whom it may concern:

Be it known that I, FRANK. A. LUNDQUIST, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Line Switches and Connections, of which the following is a specification.

My invention relates to line switches and their connections for use in automatic telephone exchanges, andhas for its object improvements in such devices.

In the accompanying drawings:

Fig. 1 is an elevation, partly in section, of a line switch and its mechanical connections;

Figure 2 is a section of the principal pneumatic device for moving the line switch;

Fig. 3 shows some of the circuit connections associated with the switch.

On a stationary frame 10 is mounted a switch frame 11 on which are brackets or extensions for holdingdiflerent parts of the apparatus. On one of these brackets, 12, is secured a socket'13, and upon this is Secured a piece of tubing 14 (Fig. 2). Mounted to slide freely on the tube 14-is an outer tube 15 which has its upper end closed, and which has secured to it a rack bar 16.

Entering the side of the socket is an air tube 17 for admitting compressed air to the interior of the fixed tube 14. When air is so admitted the outer tube 15 and its rack 16 are moved upward.

The lower end of the rack bar 16 is secured to the outer movable tube 15 by a bracket 18 and to this bracket are secured two upwardly extending arms 19 and 20. On the arm 19 are two insulated wipers 21 and 22, and on the arm 20 aretwo similar insulated wipers 23 and 24.

Secured on the stationary frame 10 is another frame 29 which carries four sets of contact strips 25, 26, 27 and 28. .These contact strips are bank contacts to be engaged by the wipers 21, 22, 23 and 24 when they are moved upward by compressed air acting 'on tube 15.

Supported on a bracket 30 is a magnet having two windings 31 and 32.; When a current fiows through these windings, the attraction of the'armature 33 moves the in 34 of an air valve in the casing 35. T 'is action opens the valve in' said casing and permits compressed air to flow from a source through pipes 36, 37 and 17 to the interior of tubes 14 and 15 to move the wipers upwards.

Supported on an extension 38 of the frame 11 is a magnet 39 arranged to be actuated when the upwardly moving wipers come into engagement with an idle trunk. WVhen this occurs, the attraction of the armature 40 moves the pawl 41 into engagement with the teeth of the bar 16' and stops the upward movement with the wipers in engagement with the idle trunk.

On the armature 40 is an arm 42 which, when said armature is attracted, engages a pin 43 to open a valve in the casing 44 and permit compressed air to flow from pipe 36 through pipe 45 and casing 44 to a pneumati'c apparatus 46 of the same general character as that described as moving the wipers .upward. The action of the compressed air in this case is to move the outer member 47 to the left and shift the adjacent contact springs to their alternative position.

Pivoted at 48 is a lever 49 which has its upper end between two collars on the movable member 47 for shifting the contact Springs just mentioned. The lowerend 50 of the lever 49 is closely adjacent to the rack 16 so that when the member 47 moves to shiftthe contact springs it pushes the end 50 into engagement with the teeth of the rackto hold it against downward movement as will be. explained.

Pivoted at 51'is a lever 52 which has one end under a pin 53 on the movable member 15, and the other end adjacent to a pair of contact springs. When the member 15 is at its lower or normal position, pin 53 bears on the lever 52 and causes said lever tohold said springs in electrical connection with, each other. But when the member 15 rises, the pin 53 is removed and the electrical connection is broken between said springs.

device 55. On the movable member 56 of this device is pivoted an arm or plunger 57 which slides on the lever 52 and engages the lever 49 to push the end'50 into the rack 16 when the arm 42 on armature 40 engages pin 43 1701013611 the valve in casing 44. But

if the rack has already been moved from its normal position, then the removal of the .pin 53 permits the outer endof the lever 52 to fall with the consequence that the arm 57 drops'below the lever 49 and accomplishes. nothing when the pneumatic device 5556 operates. In other words, if the rack 16 is in its normal position when the armature 4:0 is attracted, then the pneumatic device 55-56 pushes the end 50 into engagement with the rack to prevent its removal from normal position. But if the rack has'already been moved, then the operation of the pneumatic place in the valve casing a l, but is preferably around the pin 43'. henthe arinature 40 is in its retracted position the interior of pneumatic device 46 is in communication with the exhaust opening, but

when the arm'ature'is attracted the valvefis shifted so as to close the exhaust and open the connection between pneumaticdevice 456 and the supply of compressed air. Any valve which will shift theconnection from one channel to another will serve the purpose. A valve of thiski'nd is "shown and described in detail in my pending application Serial Number 244,731, filed July 13, 1918; and another similar valve is shown and described in my application Serial Number 250,873, filed Auguste, 19"18.

Referring to Fig. 3, the lines 59 and 60 represent the lines running from the subscribers local station to his line switch in the central oflice. lVhen the subscriber removes his receiver he connects line 59 to line 60 whereupon acurrent flows: battery X v-32- 6162 63-59 -sirb'sc'ribe1"s sta- .tion--60-64-65-66-'-31-K. V r

This current through the line'relay 3'132 causes an attraction of the armature 33 to open the valve in casing 8 5 and perinit compressed air to flow tothe pneumatic device 15, whereupon the wipers are carriedup ward to engagement with some idle trunk. an adjusting screw 37* in pipe 37 regulates the flow of air through saidpipe.

The Y. battery X is shown again at X. G'onseq-ue-ntly, tracing a. circuit from one side of X to the other side of X is; simply tracing a circuit from one side to the other of the same battery. c

On the end of each trunk is" a selector switch which, in idle position,-' has contact springs 69 and in contact with each ether. When the line switch: wiper's inmovirig'ii pward come into ehga emene with as idle trunk a current flows: battery X-67 -68- 69.7071-co'ntact strip 25- 2172-73' The current through the magnet 39 attracts the armature fit) to throw the pawl ll into theteeth of the bar 16'to stopthe wipers on the found trunk, and also to cause arm 42 to open the valve in casing 44. The com pressed. air then moves the member 47 to shift the adjacent contact springs,and also to move lever 49 so that its end 50 will also engage the rack-teeth on bar 16. The compressed air also flows through pipe 54 to move device 56, but this is without effect at this time because the previous upward move- 'm'ient of tube 15 had removed pin 53 from lever 52 so that plunger 57 fell below the end (if lever 49.

As soon as men'iber' e17 shifts the adjacent COHtaCt springs anew circuit is com pleted as follow'sz battery K -"magnet 77}- 78 27 23 -79 80 63 59 subscribers station-6064;- 81- 82-2428 83 re sistance 8 X. v p y The magnet 77 on the selector corresponds to the magnet 31 32 on the line switch and causes the selector to advance from its normal position so as to: break the circuit for magnet 39 at the contact springs 69 -70. But the'mo-vement of the armature 85 which starts the selector to break this circuit closes adjacent contactsprings' 86-87 to make a new circuit as folbWsz-battery X'-67- 8687 88+26 22 899O74 7539 TG X. At the time the member 47 shifted the contact springs, as described, it-broke the circuit forl'mag net 3132, the efiect of which was to permitlthe valve in casing 35 to return to its normal position. The return o-fthis valv eshuts off the air pressure and opens'theexhaustunder the member 15. The fall o-f this member with its attached wipers is prevented the fact that the member 47 tilted lever 49 to thrust end 50 into the teeth of bar 16; From the circuit connections so far given 59 is connected through 79 to the wire 91 leading to the next switch. Also, that" the local station wire 60 is connected through the local station, and this magnet, as far as its armature 85' is concerned, is" a slow magnet with the result that the armature 85 remains attracted during calling and talking. Consequently, this-arinature' holds s rings Strand 8? closed and maintains magnet ,ZfiQ' energiZed'. When' the subscriber strip his receiver he breaks the ircuit. for 'Z; and=.this in tum Breaks the circuit it will be seen that the local station wire 7 which a calling subscriber talks to the subscriber reached by wires 59 and 60. The wire 95 1s a cut out wire extending from the .private bank contacts of the connector switch to the line switch of the called subscriber. The calling subscriber has battery connections on his cut out wiper by an arrangement which is not a part of the present invention and need not be described in detail.

When this wiper engages the terminal of line 95 a current flows over 959697- 75-3976X.

The consequent operation of magnet 39 attracts armature 40 to'throw pawl 41 into rack 16 to prevent it from moving from its normal position. Also to shift the valve in casing 44 to admit compressed air under member 47 so as to cause it to shift the adjacent contact springs from the normal position shown to their alternative position. In this alternative position the wire 93 is connected to wire 59, and 94 is connected to 60.

WVhat is just given represents what occurs when the called subscriber has his line switch in normal position. If, however, the line switch has been previously moved from its normal position, then the pin 53 has left lever 52, and this lever has permitted con tact springs 96 and 97 to open. Under these conditions the calling connector can find no connections over wire 95.

Returning now to the conditions in which the line switch under consideration belongs to the called subscriber, it will be observed that if the calling subscriber hangs up his receiver before the called subscriber does, then the circuit will be broken through magnet 39 and pawl 41 will fall back from rack 16. Also that the compressed air will be exhausted under member 47 so that said member and the adjacent contact springs will return to normal position. Under these conditions a circuit will be established through magnet 3132 as in the first instance, and compressed air will be admitted under member 15 to start the line switch on a trunk hunting expedition. But when air was -first admitted to 46-47 by a circuit established by a connector, it was also adn Lil ted to 55 56, and this occurred when lever 52 was in its normal position Under these conditions the plunger 57 is forced against the back of lever 49 to hold its end 50 in the rack 16 and thereby prevent a trunk hunting movement. When the circuit was broken through magnet 39, air was quickly exhausted under member 47, but the check valve 58 prevents the exhaust under member 56 when occurring so rapidly. This delay permits the compressed air to start to raise 15 before the end 50 can be withdrawn from the teeth of bar 16. Underthese conditions the parts lock themselves against a trunk hunting movement of the wipers. In the specific construction illustrated this self" locking is due to the fact that the end 50 is offset from the center 48 and has moved up ward on the arc of a circle having 48i'or a center. A tooth of bar 16 striking under the end 50 simply acts to drive it tighter against the bar 16 in which position it is helduntil the called subscriber hangs up his receiver.

In telephone exchanges frequently constructed, the line switches each have two relays permanently bridged across the line lead ing from the line switch to its local station. These relays are high wound and expensive. In this line switch the only thing corresponding to the ordinary line relays is the magnet or relay 3132. But the construction' and connections are such that when the wipers find an idle trunk the magnet 31- 32 is entirely out out and is no longer bridged across the line. Because it is not bridged across the line during subsequent operations, the magnet 31-32 may be low wound and cheap in construction. In other words, in this construction I am enabled to substitute one cheap magnet for two expensive relays without sacrificing anything in efficiency.

It is observed that the magnet 39 acts as a selector for idle trunks in calling, and as a connector when the subscriber is called. In selecting it throws the pawl 41 into the rackto stop the wipers on an idle trunk, and also acts through air pressure devices to shift the adjacent contact springs so as to extend the subscri-bers line to the next switch. As a connector it acts, through air devices, to shift the subscribers line from his magnet 31-32 to the callingline. As magnet 39 is operated by local battery and is not con nected to the talkingcircuit, it may be low wound and cheap in construction.

In addition to magnet 39 acting at one time as a selector and at another time as a connector, it acts under both conditions as a cut-out to disconnect the starting magnet 3132 from the talking circuit.

What I claim is:

1. In a switching mechanism, a power device for moving the movable part thereof, an intercepting device for stopping such part, a locking device for holding it when stopped, a pneumatic device for operating the locking device, and a magnet for operating the intercepting device and controlling the pneumatic device.

2. Bank contacts, a wiper, means for moving the wiper to engagement with successive contacts, an intercepting device for arresting the movement of the wiper, and locking devices for holding the wiper from movement after the stopping device is removed. Y

from stations other than that with. which the line switch is associated.

4. In a line switch of a telephone exchange, a locking device arranged to hold the switch. in whatever position it happens "to be at the time the locking device is actuated, and means by which. said locking device may be actuated from any local station in the exchange.

5. In a line switch associated with alocal station, a locking device for holding said switch against movement, means by which said device may be actuated from other stations to lock the switch, and means: by which said locking device is released only from the station with which it is associated.

6. In a switching mechanism, wipe-rs, a power device for moving said wipers, a magnet, means for operating said magnet, an intercepting device actuated by said magnet for stopping the movement of said wipers at a desired point, and a locking device operated in response to the operation of said magnet for locking said wipers against movement at said point after the power is removed.

7. In a line switch associated with a local station, a looking device for holding said switch against movement, a pneumatic device for operating said locking device, and

ravages line, a switch individual thereto, a relay in said switch and normally in bridge of said line for starting the operation thereof,

a locking device and a pneumatic device in sa1d switch, other subscribers lines, and

means for operating said pneumatic device from any of said lines to operate said looking device to lock said switch against movement and to remove said relay from in bridge of said line. v

9. In a line switch individual to a subscribers line, a relay normally in bridge of said line, means for operating said relay to start said switch into operation, a mag net, means for operating said magnet to stop the operation of sa-id switch, a pneumatic device operated by said magnet to lock said switch against movement and to femove said relay from in bridge of said 10. A pipe having branches and provided with air under pressure, a pneumatic motor connected to one branch and a second pneumatic motor connected to another branch, a valve for each branch, means for opening one valve to cause. the operation of one motor, and means: controlled by the stoppage of such operation for opening the other valve.

FRANK A. LUNDQUIST. 

